Russia expects the United States to lift bans on trade with four Russian companies if Moscow backs new sanctions against Iran, a senior Kremlin official said on Friday.

The official said Russia wants "the swiftest removal" of U.S. sanctions against Russian state arms exporter Rosoboronexport and three other enterprises he indicated were under U.S. restrictions aimed at preventing weapons proliferation.

"We will demand it -- seeing as they are counting on our position in working out (measures) against Iran with the international community," the official told reporters, speaking on condition of anonymity.

The United States and Western allies are seeking support from Russia, a veto-wielding permanent U.N. Security Council member, for a fourth round of Security Council sanctions against Iran over its nuclear program.

Russia has indicated it could support sanctions but stressed they must not harm the Iranian people.

Russia has long criticized sanctions against Rosoboronexport and other firms accused of selling technology that could help Iran, Syria or North Korea develop weapons of mass destruction or missile systems.

Russia says none of its weapons sales violate international law or non-proliferation rules.

The Kremlin official named Rosoboronexport and the Moscow Aviation Institute and said two other Russian enterprises that he did not name were also under U.S. sanctions.

Documents on the U.S. State Department website indicate sanctions imposed on Rosoboronexport in 2008 under the Iran, North Korea and Syria Nonproliferation Act remain in place.

At the time, President Dmitry Medvedev called the restriction short-sighted and said they would not seriously hurt sales.

Web-posted U.S. Treasury Department documents indicate the Moscow Aviation Institute is covered by an order barring imports from entities and individuals accused of weapons proliferation.